Hard starting when cold??

[speedy341]

Last year my bike would start right up, hot or cold. When it was
cold, I'd choke it, start it, then it'd rev (by itself) to about
4000rpm, i'd shut the choke off and it'd be ready to ride.

This year it takes 10 minutes to get it going when it's cold. It
starts fine when it's hot.

I have to fully choke it, and it barely runs on it's own, about
700rpms. If I slowly take the choke off it dies. I have to go
through this ritual of starting it, giving it a TINY bit of gas, and
slowly taking off the choke. After about 20 times with it dying, it
will finally get going and run fine.

I'm tired of being late for work, and I'm sure my neighbors
want to kill me.

Any ideas?

Oh, BTW, I put in new spark plugs and new gas (I Stabil-ed it last
year) but it didn't help.

 

[47HO]

Sounds like you might have an intake leak somewhere, always leaning the motor out. This condition would be exaggerated when the engine is cold.

 

[shortyb]

What kind of bike? Sometimes carb pilot circuits can get clogged, they are very small, and could cause cold start problems like you mention. It could be from a small speck of dirt and not necessarily from the storage either.

 

[tmorris1]

quote:

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Sometimes carb pilot circuits can get clogged, they are very small, and could cause cold start problems like you mention. It could be from a small speck of dirt and not necessarily from the storage either

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I think this is on the right track. When you choke it you are using a circuit that bypasses the pilot jet.

 

[speedy341]

Thanks for the input!

It's a '87 Honda VFR 700.

I had a float bowl off a few weeks ago (to fix a leaking gasket) and the insides looked clean.

Someone else told me about the choke circuit possibly being blocked. I got the bright idea of choking it while riding with the motor at about 9500 rpms. It acted like I would expect with the choke on, bogging, hesitating, etc. That was the last time I rode it. It seemed to start a little easier this morning. I was hoping to (maybe) clean out the choke circuit with it running.

I really don't want to tear into the carbs because I heard on these old V4 engines it's difficult to get them back on because the intake boots get hard and brittle. This problem is magnified because of how the carbs sit in-between the cylinders (V4 not much room to work to get the carb bank back in). I'd rather not open that can of worms, but if it must be done, I'll do it and hope for the best.

 

[tmorris1]

If it runs with the choke until you shut it off the choke is not plugged. You need to take it apart and hold the jets up to light before you can see any blockage, they are really small. Is your air filter by any chance plugged?

 

[speedy341]

You know, I never even thought about the air filter because I put a new one in last year.

Maybe something crawled up there over the winter and made a nest. It wouldn't be the first time that happened.

I'd be stoked if it was as simple as thet!

 

[2manydogs]

This is VERY crude, but if your carbs are NOT diaphram-style, try it. Open the float drains (gas off) Remove the spark plugs. Close the choke. Turn the engine over until the intake valve is open on say, #1 cylinder. Use a rubber tipped air gun and blow into the spark plug hole for a few seconds. Open the intake valve on the next cylinder and repeat. Do the remaining cylinders. Turn on the gas and flush out the float bowls. Put 'er back together and try it. This is the reverse of the 'high RPM,choke on tune up'. It will usually clear any crud out of the main jet. Be gentle but firm with the air pressure. The things I've done to avoid taking apart a pain in the butt carb

Jim

 

[2manydogs]

Forgot to mention to have the throttle wide open- and make sure it's on the intake stroke and not the overlap. You want to build positive pressure in the intake system. This will also let you find any intake leak like was mentioned above. Jim